JPH0442811B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a conductive paste for ceramic capacitors. (Prior Art) Conventionally, as a conductive paste for electrodes of ceramic capacitors, 100 parts by weight of zinc powder and glass powder have been used, for example, as described in JP-A-58-196.
0.01 to 10 parts by weight and organic titanium compound [Ti(O-
At least one of C ₁₇ H ₃₅ ) ₄ and (O-C ₄ H ₉ ) ₄ ]
0.01 to 14.99 parts by weight and metal oxides (Pb ₂ O ₄ ,
At least one of Bi ₂ O ₃ , Pb ₆ O ₁₁ , CuO, CdO)
Those comprising 0.01 to 5 parts by weight and 30 parts by weight of vehicle are known. To form the electrodes of a ceramic capacitor using this conductive paste, for example, the diameter is 10 mm and the thickness is 0.3 mm.
The conductive paste is applied to two surfaces of dielectric porcelain such as strontium titanate, and approximately
Bake at around 700℃. However, the solderability of the electrodes is not good if left as is, so the film formed by baking is immersed in an ordinary chemical plating solution that does not contain ethylenediaminetetraacetic acid (EDTA) or a chemical plating solution that contains EDTA. to form a copper coating. (Problems to be Solved by the Invention) As mentioned above, although the soldering strength of electrodes using conventional chemical plating solutions that do not contain EDTA is sufficiently high, the plating solution lacks stability and The problem was that self-decomposition of the liquid occurred quickly, and the liquid had to be replaced with a new one each time it was used. On the other hand, plating liquids containing EDTA are highly stable and can be used repeatedly, so they have recently come into widespread use. However, when a copper film is formed on a zinc electrode using this plating solution, there is a problem in that the soldering strength of the electrode is weak. For example, using this plating solution, the tan δ of a 6 mmφ disc ceramic capacitor plated with copper on a zinc electrode can be
was 2.5%, and the tensile strength of the lead wire soldered to this electrode in the direction perpendicular to the electrode surface was 0.6 kg. The present invention is suitable for producing an electrode for a ceramic capacitor having a copper coating formed by a plating solution containing EDTA, and the tensile strength of the electrode by a lead wire connected to the electrode is 1.4 kg or more and tan δ is 1.15% or less. The purpose is to provide a certain conductive paste. (Means for Solving the Problems) The present invention is characterized in that it consists of 100 parts by weight of zinc powder, 15 to 25 parts by weight of an organic titanium compound, 0.1 to 5 parts by weight of titanium oxide powder, and 15 to 20 parts by weight of a vehicle. shall be. (Example) Example 1 The conductive paste of this example is made of zinc (Zn) powder.
100g, 3g of titanium oxide (TiO ₂ ) powder, and α-
Weighed 15 g of a vehicle in which 20% by weight of ethyl cellulose was dissolved in terpineol, put it in a crusher, and kneaded it for 1 hour.
-Butoxytitanium monostearate Ti
20g of (OCOC ₁₇ H ₃₅ )(OC ₄ H ₉ ) ₃ was added and kneaded for an additional 15 minutes. The conductive paste was applied to almost the entire surface of both main surfaces of strontium titanate porcelain with a diameter of 10 mm and a thickness of 0.3 mm using a screen printing method, and then baked in air at a temperature of 700°C for 30 minutes to form electrodes. was formed. Next, a chemical plating solution (PH11, bath temperature) consisting of copper sulfate, sodium hydroxide, formalin, and EDTA was applied.
65° C.) for 20 minutes to form a 1 μm copper plating film on the electrode. One hundred such ceramic capacitors were made, and a 0.5 mm diameter lead wire was soldered to each electrode surface. And for these capacitors, their tanδ
and measured the tensile strength of the electrode. tanδ is a commercially available LCR meter (YHP 4274A)
Measurements were made using a measurement frequency of 1KHz. No. 1 in Table 1 shows the largest value of tan δ among the 100 samples. To measure the tensile strength of an electrode, connect the lead wire of the capacitor whose tanδ was measured to the measurement terminal of a push pull gauge, pull it perpendicular to the electrode surface, and read the value (Kg) when the electrode breaks. It was defined as strength. No. 1 in Table 1 had the smallest tensile strength. Example 2 In Example 1, organic titanate tri-n
-Butoxytitanium monostearate Ti
It was produced in the same manner and under the same conditions as in Example 1, except that (OCOC ₁₇ H ₃₅ )(OC ₄ H ₉ ) ₃ was changed to 25 g. The results are shown in No. 2 of Table 1. Example 3 In Example 1, 5 g of titanium oxide powder and 15 g of tri-n-butoxytitanium monostearate were used.
It was produced by the same method and under the same conditions as Example 1 except for the following. The results are shown in No. 3 of Table 1. Example 4 In Example 1, 0.1 g of titanium oxide powder,
Tri-n-butoxytitanium monostearate 15
It was produced by the same method and under the same conditions as Example 1, except that g was used. The measurement results are shown in No. 4 of Table 1. Example 5 Tri-n- of organic titanate in Example 1
Titanium lactate ethyl ester Ti(C ₅ H ₇ O ₂ ) ₂ instead of butoxytitanium monostearate
Same method as Example 1 except that (C ₅ H ₉ O ₃ ) ₂ was used;
It was made under the same conditions. The measurement results are shown in No. 5 of Table 1.

[Table] In addition to the above examples, Ti of organic titanium compounds
As for those having the (L) ₂ X ₂ structure, titanium octylene glycolate, polytitanium acetylacetonate, titanium lactate ethyl ester, phenoxytitanium-ketoester chelate, etc. exhibit similar effects. In addition to the above examples, those with Ti( _OCOR ) n It was shown to be effective. In addition, organic titanium compounds have a Ti(L) ₂ X ₂ structure and a Ti
(OCOR) A mixture of nX ₄ -n structures also showed similar effects. If the amount of the organic titanium compound relative to the zinc powder is less than the above range, the tan δ will be worse than 1.15% and the tensile strength of the electrode will be less than 1.4 kg. If the above range is exceeded, the coating film of the conductive paste will crack during firing, the plating solution will penetrate into the coating film, and both tan δ and tensile strength will fall below the above values. If the amount of titanium oxide is less than the above range, the tan δ will be worse than the above value, and if it exceeds the above range, the viscosity will increase and the printing performance will deteriorate, which is not preferable. Furthermore, if the amount of vehicle is outside the above range, the viscosity will be low or high and printability will be lacking. (Effects of the Invention) As described above, the present invention is suitable for producing an electrode for a ceramic capacitor having a copper coating formed with a plating solution containing EDTA, and the tensile strength of the electrode is
It has the effect that it weighs 1.4Kg or more and tan δ is 1.15% or less.

Claims (1)

[Claims] 1. 100 parts by weight of zinc powder and 15 to 15 parts by weight of an organic titanium compound
A conductive paste for a ceramic capacitor, comprising 25 parts by weight of titanium oxide powder, 0.1 to 5 parts by weight of titanium oxide powder, and 15 to 20 parts by weight of a vehicle. 2 Organotitanium compounds are Ti(L) ₂ X ₂ and Ti(OCOR) _n The conductive paste for a ceramic capacitor according to claim 1, characterized in that the conductive paste is at least one kind.